There currently exist several solutions for fixing a wristlet to a watch case.
First, attaching systems achieved by means of melting the watch case with the attaching link in a single piece are known; however, in such case, the production costs are extremely high, since moulds which provide a suitable shape, for example comprising extensions protruding from the perimeter of the case, suitable for fixing the wristlet, are necessary.
There also exist attaching systems for plastic or leather straps and for metal wristlets comprising, usually, two pins, situated on diametrically opposite parts of the watch case, within housings, which are machined directly on the case or externally on the perimeter.
The strap (or wristlet) comprises a passage wherein the pin for fixing such strap or wristlet to the case is inserted.
In all the cases described, however, the wristlet comprises a link for attaching it to the watch case, which has a housing wherein the fixing pin slides.
It is therefore clear that the relative friction between two metal materials, of which the wristlet and the fixing pin are made, induces considerable mechanical fatigue and stress, especially when the watch is put on the user's wrist and when the wristlet is assembled or when components thereof are changed.